1. Field of the Invention
The invention relates to the field of footwear, such as shoes and boots, and, more particularly, the field of sports footwear.
2. Description of Background and Relevant Information
A typical article of sports footwear includes a sole, which can be either flexible or rigid, and an upper for covering the wearer's foot mounted thereon. The upper is typically constructed in the form of a plurality of elements that are cut out and assembled to one another so as to form a three-dimensional envelope that is as close to the shape of the foot as possible. Generally, the shapes of these elements and their constituent materials are dictated by the position of the elements in the shoe or boot, and by the function they are adapted to perform. The upper can also have additional elements attached, such as a front end reinforcement, which are generally made of thick leather or rubber.
The upper of most articles of sports footwear includes medial and lateral quarters that are adapted to be brought toward one another by a tightening mechanism, generally in the form of lace. The quarters are separated by a longitudinal slit beneath which a comfort tongue extends.
In certain types of footwear, such as cross-country ski boots and certain hiking shoes and boots, the upper includes a protective flap that covers the tightening mechanism/lace, but which can be moved aside to enable lacing and unlacing, to facilitate putting the shoe on and taking the shoe off. Such protective flap is particularly useful for articles of footwear that are adapted to be worn in snow, as it prevents the snow from infiltrating into the footwear in the area of the slit that separates the medial and lateral quarters of the upper.
In a conventional design, the various constituent elements of an upper are essentially assembled by sewing/stitching. To this end, the elements to be assembled have overlapping portions by which two adjacent elements are superimposed. A through-seam, that is, a seam that is visible on both sides of the stitched superimposed portions, connects the two elements to one another. With a through-seam, the sewing thread is exposed on both surfaces and, therefore, on the outer surface of the upper, in particular. It is thus exposed to external attacks, in particular to friction that can wear out the thread and, therefore, cause the seam to rupture. Similarly, through-seams constitute points of entry for moisture to infiltrate into the footwear.